Discoloured water observed near Nanpo Shoto at 31-26.4N 140-03.0E on September 18, 2024 at 0545Z. Vessels advised caution.
Philippine Sea · NAVAREA XI 491/24
What this record establishes
Listed in force
The latest collected record lists this warning as active. This is the status of the notice, not a live observation of conditions at the location.
- Source and dates
- Japan Coast Guard JHOD NAVAREA XI · Japan Coast Guard (JHOD). Issued 2024-09-19 02:00Z. First collected 2026-08-17 13:42Z; last seen in collection 2026-08-17 14:24Z. Collection dates record ingestion, not a new incident or a fresh field observation.
- Location covered
- Philippine Sea. The parsed report position is 31.440, 140.050. It is a position in the source message, not a live location. Check the original wording for limits and qualifications.
Related notices and cancellation links
These reports were linked by category and sea, with positions within 30 nautical miles and issue dates within 30 days of another report's recorded in-force span. Links can extend through other members, so the full group can cover a larger area or period. Proximity does not confirm that they describe one incident.
- NAVAREA XI 491/24 · this notice2024-09-19 · Listed in force
- NAVAREA XI 492/242024-09-19 · Listed in force
- HYDROPAC 3071/242024-09-19 · Cancelled notice
- HYDROPAC 3072/242024-09-19 · Cancelled notice
Current notices and reporting history in the Philippine Sea →
- issued
- 2024-09-19 02:00Z
- status
- Listed in force
- authority
- Japan Coast Guard (JHOD)
- NAVAREA
- NAVAREA XI
- issued by
- JAPAN COAST GUARD
- sea
- Philippine Sea
- position
- 31.440, 140.050
- nearest port
- Shimizu · 228 nm
- source
- Japan Coast Guard JHOD NAVAREA XI · first seen 2026-08-17 13:42Z
Original warning text
NORTH PACIFIC, NANPO SHOTO. DISCOLOURED WATER OBSERVED IN VICINITY OF 31-26.4N 140-03.0E AT 180545Z SEP. VESSELS REQUESTED TO BE CAUTION ADVISED. CANCEL 0369/24.
Reading this warning
- Discoloured water
- Patches of unusually coloured sea — often a sign of a submarine volcano or of a shoal.
- Position (degrees and minutes)
- How warnings write positions: degrees, a hyphen, then minutes, with N/S and E/W — 49-40.8N 003-43.8W.
- Date-time group (DTG)
- A compact UTC timestamp — day, hour and minute followed by Z — such as 201500Z for the 20th at 15:00 UTC.
Nearest volcano
Bayonnaise Rocks · 51 km
Conditions at the position · now
loading…
MET Norway · NOAA WaveWatch III · HYCOM · GEBCO 2020 · model data at the centroid, not an observation
Collected reports in this area · volcanic activity
12 within 180 nm since 2001 · 0 in the last 12 months · 2 listed in force now
Counts include repeat notices about the same situation. NGA archive coverage ends 2024-05; live collection began 2026-08-17. The period between them is incomplete. An empty year is not evidence that no hazards occurred.
- Possible volcanic activity reported in 31-26.30N 140-03.00E2024-09-19
- Discolored water reported in 31-26.40N 140-03.00E at 180545Z sep2024-09-19
- 180500Z issued at 190200Z sep2024-09-19
- Possible pumices adrift in vicinity of trackline joining 30-41.00N 139-51.00E, 30-24.00N 139-45.00E,…2023-10-20
- Possible pumices adrift in vicinity of trackline joining 30-41.00N 139-51.00E, 30-24.00N 139-45.00E,…2023-10-20
- Discolored water in vicinity 31-54.5N 140-01.6E at 240250Z mar2017-03-24
Month of issue in the collected archive
All available years combined. Uneven collection and repeat bulletins affect these counts; this chart does not measure the seasonality or probability of incidents.
Nearby notices listed in force · within 120 nm
- 180500Z issued at 190200Z sepVolcanic · 0.1 nm
Worldwide in the collected sources
12 volcanic activity listed in force · see all
Record snapshot 2026-10-01 10:39Z; source collection times vary.
Volcanic
Submarine eruptions, discoloured water, pumice rafts. All current volcanic activity →
Not for navigation. This is a re-rendering of an official navigational warning for awareness; mariners must use official NAVAREA broadcasts and their national MSI service.